This invention relates to a therapeutic composition, methods for its preparation and for its use. More particularly, this invention relates to an emulsion of marine oil for treatment of thrombotic disease.
The therapeutic use of intravenous (IV) lipid emulsions in the clinically ill has its origin in antiquity. Physicians originally attempted infusions of olive oil and milk into the blood stream of critically ill patients in the 1600s and 1700s. The therapeutic reason for these infusions was to prevent starvation, often the deciding factor in the survival of such patients. Lipid is an attractive nutritional high calorie source (9kcal/g) as compared to carbohydrate (4kcal/g). These early experiments were unsuccessful due to severe adverse reactions. A long search for an appropriate lipid source for clinical nutrition ensued.
Various oil sources including butter oil, coconut oil, cottonseed oil, lard oil, olive oil, sesame seed oil, safflower oil and soybean oil, containing esters of fatty acids (6-22 carbons long) were tried. Also various emulsifying agents including soybean phosphatides, sorbitan monolaurate, polyglycerol esters of fatty acids, gelatin, cholesterol, sodium cholate and egg yolk phosphatides which are necessary to allow solubility of these lipids in an aqueous environment such as the blood stream were employed. (Thompson, S. W. The Pathology of Parenteral Nutrition with Lipids. Springfield, IL: Charles C. Thomas, 1974) This search was at first unsuccessful due to impurities such as high free fatty acids found in these primitive oils and emulsifiers. Over the last thirty years this search has focused on two possible oils and emulsifiers that showed therapeutic potential. The first of these were liquid emulsions composed of cottonseed oil (10 to 20% wt/v), soybean phospholipid (1-5% wt/v) and glycerin (2.25% w/v). Early emulsions of this composition showed a high degree of toxicity in both animals and man. (Meng, H. C. and J. S. Kaley., Effects of Multiple Infusions of a Fat Emulsion on Blood Coagulation, Liver Function, and Urinary Excretion or Steroids in Schizophrenic Patients. J Clin Nutr 16: 156-164, 1965) Since then such emulsions have undergone improvements. Both the oil and emulsifiers have been further characterized and purified and presently appear to provide a therapeutic modality to supply calories to the critically ill. (Lipofundin S. Fat Emulsion for Parenteral Hyperalimentation and Supply of Polyunsaturated Essential Fatty Acids. Germany: B. Braun, 1981) However, due to their notorious past, emulsions of such composition are little used in clinical nutrition.
The second emulsion which evolved during this period was one composed of purified soybean oil (10-20% wt/v), egg yolk phospholipids (1-5% wt/v) and 2.25% w/v glycerin. This emulsion, due to the purified nature of its components, produced clinically acceptable results as a calorie source in clinical nutrition. (Wrentlind, A. Current Status of Intralipid and other Fat Emulsions. pp109-122 in: Fat Emulsions in Parenteral Nutrition. Meng, H. C. and Wilmore, D. W., ed. Chicago, American Medical Association, 1976) This emulsion then established lipid emulsions as a viable nutrition therapy, and several emulsions of this composition are presently on the market. Recent additions to this family of lipid calorie sources are compositions of safflower oil and mixtures of soybean and safflower oils which appear to be viable emulsions as well. (Ament, M. E., R. A. Cannon, and W. J. Byrne. Use of Intravenous Safflower Oil Emulsion (Liposyn 10%) as an Energy Source in Pediatric Patients on TPN. (p165 in Parenteral Nutrition in the Infant Patient. North Chicago, IL: Abbott Laboratories, 1983)) From this historical summary it would appear that the nature of the oil and emulsifier appear to be less important than their purity for their use in clinical nutritions.
As the emulsions were developing, the biochemistry of lipids was also evolving. This resulted in the discovery of the biological essentiality of certain polyunsaturated fatty acids [linoleic acid (C18:2 omega 6), arachidonic acid (C20:4 omega 6)]. (Holman, R. T. How Essential are Essential Fatty Acids. J Amer Oil Chem Soc, 55: 744A-781A, 1978) It was observed that lack of these essential fatty acids produced a clinical syndrome characterized by scaliness and lesions of skin, cessation of growth, renal degeneration, structural and metabolic changes in the central nervous system, increased metabolic rate, weight loss and finally death. (Caldwell, M. D. Human Essential Fatty Acid Deficiency: A Review in Fat Emulsions in Parenteral Nutrition. Meng, H. C. and Wilmore, D. W., eds. Chicago, IL: Amer Med Assoc, p24, 1978) More recently, the essentiality of linolenic acid (C 18:2 omega 3) has been postulated. Deficiencies in this fatty acid cause optical and neurological disturbances. (Neuringer, M., W. E. Connor, C. Van Patten, and L. Bostad. Dietary Omega 3 Fatty Acid Deficiency and Visual Loss in Infant Rhesus Monkeys. J Clin Chem 73: 272-276, 1984). These developments further increased the therapeutic utility of lipids in clinical nutrition.
The fat emulsions outlined above have been used successfully both as a calorie and an essential fatty acid source for the last twenty years. (Pelham, D. Rational Use of Fat Emulsions. The Hosp Pharm Forum 10:1, 1981) Problems associated with their use are generally considered to be due to lipid overload. This is when concentrations of lipid in the emulsion or its metabolic products (free fatty acids) are such that the body is unable to metabolize them. (Alexander, C. S. Fat infusions: Toxic Effects and Alterations in Fasting Serum Lipids following Prolonged Use. Arch Intern Med 107: 94-514, 1961) This results in lipid accumulation in various cells, tissued, and organs of the body. (Belin, R. P., B. A. Bivins, J. Z. Jona, V. L. Young. Fat Overload with a 10% Soybean Oil Emulsion. Arch Surg 111: 1391, 1976) High levels in the blood of the emulsion's by-products, free fatty acids, have been shown to cause both cardiac and lung damage. (Soloff, L. A. Arrhythmias Following Infusions of Fatty Acids. Amer Heart J 80: 671, 1970; Broe, P. J., T. J. K. Toung, S. Margolis, S. Permutt and J. L. Cameron. Pulmonary Injury Caused by Free Fatty Acid. Evaluation of steroid and albumin therapy. Surgery 89: 582, 1981)
Fat emulsions are recommended clinically to be used at dosages of 2.5 g/kg/24 hours for adults and up to 4 g/kg/24 hours for children. (TRAVAMULSION 10% I.V. fat emulsion product insert. Deerfield, IL: Travenol Laboratories, 1985) These emulsions contain no more than 5 meq/liter of free fatty acids. The dosage level of these emulsions are recommendations and each patient must be monitored for the build up of emulsions and free fatty acids during infusion to assure safety of such therapies. Extensive studies to assess the metabolism and pharmacokinetics of these emulsions during infusion have been conducted and are well understood at this time. (Cotter, R., L. Martis, F. Cosmas, H. Sargent, C. Taylor, W. Remis, S. Young, W. B. Rowe, and E. Woods. Nonlinear kinetic analysis of the elimination of lipid emulsion administered Intravenously to Dogs. J Paren Ent Nutr (7(3): 244-250, 1983; Cotter, R., L. Martis, F. Cosmas, H. Sargent, C. Taylor, S. Young, W. B. Rowe, and E. Woods. Comparison of the Elimination and Metabolism of 10% TRAVAMULSION and 10% Intralipid Lipid Emulsion in the Dog. J Paren Ent Nutr 8(2): 140-145, 1984; Cotter, R. L. Martis, F. Cosmas, C. Taylor, S. Young, W. B. Rowe, and R. Johnson. Comparison of the Elimination of 10 and 20% TRAVAMULSION Lipid Emulsion from the Blood of Beagle Dogs. Amer J. Clin Nutr 41(5): 994-1001, 1985)
Presently a new generation of lipid emulsions is under development. These emulsions are designed as therapeutic modalities for clinical conditions that have high metabolic energy requirements. These conditions are a result of hormonal and biochemical aberrations that alter normal energy metabolism and shift it into a hypermetabolic state. (Raymond, R., R. Cotter, F. Cosmas, and D. Gibbons. Development of a Chronic Peritoneal Abscess Model in the Dog from Evaluation of Clinical Therapies. Fed Proc 43: 325, 1984) Such states are found in critically ill patients suffering from trauma, sepsis and burns. (Kinney, J. M. and P. Felig. The Metabolic Response to Injury and Infection. Endocrinology 3: 1963, 1979) These emulsions are composed of medium chain fatty acids (C6 to C12) esterified to glycerol to form medium chain triglycerides which are emulsified with (1-5% wt/v) egg yolk phospholipids to give a final triglyceride concentration of 10 to 20% wt/v. (Cotter, R., F. Cosmas, R. Johnson, B. Rowe, and L. Lin. A Comparison of the Elimination of Four Different Formulations of Parenteral Lipid Emulsions from the Blood Streams of the Beagle Dog. Fed Proc 44: 1146, 1985) These emulsions are of benefit in the hypermetabolic state as they supply twice as much metabolic energy per gram of lipid at a faster rate due to their unique biochemical advantage of carnitine independence, rapid betaoxidation and lack of deposition in organs and adipose tissue as compared to long chain triglycerides (C12-C24). (Cotter, R. C. Johnson, C. A. Taylor, T. Pavline, F. Cosmas, and W. B. Rowe. Metabolic Comparison of a 20% Combination Long and Medium Chain Triglyceride Lipid Emulsion and a 20% Long Chain Emulsion. Fed Proc 43: 848, 1984; Johnson, R. C., S. K. Young, R. Cotter, and W. B. Rowe. Metabolism and Distribution of Medium Chain Triglyceride Lipid Emulsion. Amer J. Clin Nutr 41: 846, 1985) Extensive research has been carried out to develop and characterize these emulsions, illustrating their metabolic advantage. (Young, S. K., R. C. Johnson, R. Cotter, and B. Rowe. Competitive Interaction Between Medium and Long Chain Lipid Emulsions. Fed Proc 43: 865, 1984).
The rapid bioavailability of lipid emulsions creates immediate biological effects and makes them attractive vehicles for acute intravenous therapies. Further studies have also shown that by reducing the phospholipid composition of the emulsion to about 0.4-0.6% a more rapid bioavailability is produced. This rapid bioavailability is produced by creating a more attractive lipid particle for apolipoprotein transfer from high density lipoproteins found in circulating blood. Such apolipoproteins are essential for control of lipid emulsion endothelial receptor binding and activation of hydrolytic enzymes at these receptor sites. The reduction in phospholipids in such emulsions results in a more rapid delivery of the emulsion to metabolism and a release of the biologically active metabolic products. This brings about a rapid biological response to these therapies.
Lipid emulsions containing marine oil have been proposed for the treatment of disorders associated with imbalances of arachidonic acid metabolites. Examples include: autoimmune syndromes; acute and chronic inflammatory diseases such as psoriasis and acute respiratory distress syndrome (ARDS); atherosclerosis, stroke, myocardial infarction, deep vein thrombosis and other cardiovascular diseases. The most notable cardiovascular risk factors include surgery, hyperlipidemic states, hypertension (stroke), enhanced platelet responsiveness, vascular lesions and occlusions, vascular spasm and diabetes. Studies have shown that populations (Greenland Eskimos) whose diets are rich in marine products are at considerably reduced risk of developing coronary heart disease. (Editorial. Eskimo diets and diseases. Lancet: 1139-1141, May 21, 1983) Such diets are rich in fatty acids of the omega three (omega 3) family. The three members of this family which appear to play a significant role in this effect are linolenic acid (C18:3), eicosapentaenoic acid or EPA (C20:5), and docosahexaenoic acid or DHA (C22:6).(Bang, H. O., J. Dyerberg, and N. Hjorne. The Composition of Food Consumed by Greenland Eskimos. Acta Med Scand 200: 69-73, 1976)
In the average European and North American diet, linoleic acid (C18:2), an omega 6 fatty acid, is the predominantly consumed essential fatty acid, accompanied by low levels of linolenic acid. Linoleic acid is converted to arachidonic acid (C20:4), both of which are incorporated into the lipid component of cell membrances and serum, and give rise to metabolites of the omega 6 pathways.
Cold water marine animals contain low concentrations of the essential fatty acid, linolenic, in their tissues and large amount of two other members of the omega 3 family: EPA and DHA. These fatty acids are also incorporated into cell membranes and serum and give rise to metabolites of the omega 3 pathways. The two metabolic pathways containing the omega 3 fatty acids are not interchangeable in animals. However, the enzymes which metabolize the omega 6 and omega 3 series seem to be identical.
Most animal cells utilize these fatty acids to form various prostaglandins and leukotrienes. (Spector, A. A., T. L. Kuduce, P. H. Figard, K. C. Norton, J. C. Hoak, and R. L. Czeruionke. Eicosapentaenoic Acid and Prostacyclin Production by Cultured Human Endothelial Cells. J Lipid Res 24: 1595-1604, 1983; Lee, T. H., R. L. Hoover, J. D. Williams, et al. Effect of Dietary Enrichment with Eicosapentaenoic and Docosahexaenoic Acids on in vitro Neutrophil and Monocyte Leukotriene Generation and Neutrophil Function. N Engl J Med 312(19): 1217-1224, May 9, 1985) When fatty acids are released from cell membranes and intracellular pools, the lipoxygenase and cyclooxygenase enzymes mediate the production of various eicosanoids. Although EPA is a relatively poor substrate for cyclooxygenase, it appears to have a high binding affinity and thereby inhibits arachidonic acid conversion by this enzyme. (Needleman, P., A. Raz, M. Minkes, J. A. Ferrendelli, and H. Sprecher. Triene Prostaglandins, Prostacyclin and Thromboxane Biosynthesis and Unique Biological Properties. Proc Nat Acad Sci USA 76: 944, 1979) On the other hand, EPA is a good substrate for the lipoxygenase enzymes. (Terano, T., J. A. Salmon, and S. Moncada. Biosynthesis and biological activity of leukotriene B.sub.5. Prostaglandins 27(2): 217-232, 1984) In either case, EPA would have clinical application in disorders associated with elevated levels of arachidonic acid metabolites (examples: thromboxane B.sub.2 mediated myocardial infarction; (Hay, C. R. M., A. P. Durber, and R. Saynor. Effect of Fish Oil on Platelet Kinetics in Patients with Ischemic Heart Disease. Lancet 1269-1272, June 5, 1982 ) and leukotrienes in psoriasis. (Brain, S. D., R. D. R. Camp, A. Kobza Black, et al. Leukotrienes C.sub.4 and D.sub.4 in psoriatic skin lesions. Prostaglandins 29(4): 611-619, 1985)
An additional application of the omega 3 fatty acid pathway lies in the physiological activities of their cellular products. EPA has been shown to lower platelet activity. (Holme, S., J. H. Brox, H. Krane, and A. Nordoy. The Effect of Albumin Bound Polyunsaturated Fatty Acids on Human Platelets. Throm Haemostas 51(1): 32-36, Stuttgart, 1984) Platelet activation and release is implicated in the pathophysiology of such cardiovascular disorders as atherosclerosis; (Ross, R., and L. Harker, Hyperlipidaemia and atherosclerosis. Science 193: 1094, 1976); thrombosis, (Hornstra, G. Dietary Fats and Arterial Thrombosis: Effects and Mechanism of Action. Prog Biochem Pharmacol 14: 326-338, 1977); myocardial infarction, (Hay, C. R. M., A. P. Durber, and R. Saynor, Effect of Fish Oil on Platelet Kinetics in Patients with Ischemic Heart Disease, Lancet 1269-1272, June 5, 1982); and shock. (Lefer, A. M. Role of the Prostaglandin-Thromboxane System in Vascular Homeostasis During Shock. Circ Shock G: 297-303, 1979)
Many short-term studies involving the daily administration of some marine products to apparently health human subjects have demonstrated similar findings to those reported for Greenland Eskimos. There is a mild bleeding defect (prolonged bleeding time) and platelet aggregation response to collagen, or ADP is markedly reduced. (Goodnight, S. J., W. C. Harris, and W. E. Connor. The Effects of Dietary Omega-3 Fatty Acids on Platelet Composition and Function in Man: A Prospective, Controlled Study. Blood 58(5): 880-885, 1981; Thorngren, M., and A. Gustafson. Effects of 11-week Increase in Dietary Eicosapentaenoic Acid on Bleeding Time, Lipids, and Platelet Aggregation. Lancet: 1190-1193, Nov 28, 1981) In nonhuman primates with advanced atherosclerosis and markedly shortened platelet survival times, the offering of a diet containing EPA resulted in the normalizing of platelet survival times. (Ward, M. V., and T. B. Clarkson. The Effect of a Menhaden Oil Containing Diet on Hemostatic and Lipid Parameters of Nonhuman Primates with Atherosclerosis. Atherosclerosis (in press))
In most normal subjects and patients who consume such diets, total serum cholesterol, very low density lipoprotein cholesterol, and triglycerides are significantly lowered. (Mortensen, J. Z., E. B. Schmidt, A. H. Nielsen, and J. Dyerberg. The Effect of N-6 and N-3 Polyunsaturated Fatty Acids on Hemostasis, Blood Lipids and Blood Pressure. Thromb Haemostas 50(2): 543-546, Stuttgart, 1983; Phillipson, B. E., D. W. Rothrock, W. E. Connor, W. C. Harris, and D. R. Illingworth. Reduction of Plasma Lipids, Lipoproteins, and Apoproteins by Dietary Fish Oils in Patients with Hypertriglyceridemia. N Engl J Med 312(19): 1210-1216, 1985) High density lipoproteins (HDL) cholesterol concentrations may be elevated in some subjects. (Sanders, T. A. B., and M. C. Hochland. A Comparison of the Influence on Plasma Lipids and Platelet Function of Supplements of Omega-3 and Omega-6 Polyunsaturated Fatty Acids. Brit J Nutr 50: 521-529, 1983) This pattern of change would be one thought to be less atherogenic.
Studies with animals have shown that those fed diets containing EPA, as opposed to commercial chows, have significantly lower infarct sizes when their coronary or carotid arteries are ligated. (Culp, B. R., W. E. M. Lands, B. R. Lucchesi, B. Pitt, and J. Romson. The Effect of Dietary Supplementation of Fish Oil on Experimental Myocardial Infarction. Prostaglandins 20(6): 1021-1031, 1980; Black, K. L., B. Culp, D. Madison, O. S. Randall, and W. E. M. Lands. The Protective effects of dietary fish oil on focal cerebral infarction. Prostaglandins & Med 3: 257-268, 1979). The difference is thought to be due to a reduced oxygen demand on the part of the affected tissue. This would support the findings from studies with nonhuman primates whereby a diet containing EPA had a sparing effect upon the onset and extent of myocardial ischemia after isoproterenol stress tests. (Ward, M. W. Unpublished finding, Bowman Gray School of Medicine, Winston-Salem, NC) In studies with human subjects fed marine products, both blood pressure and blood pressure response to norepinephrine fell significantly. (Lorenz, R., U. Spengler, S. Fischer, J. Duhm, and P. C. Weber. Platelet Function, Thromboxane Formation and Blood Pressure Control During Supplementation of the Western Diet with Cod Liver Oil. Circulation 67(3): 504-511, 1983).
Change in fatty acid composition of blood cell membranes and serum may explain some of the aforementioned physiological observations. With the ingestion of a marine diet, the omega 3 fatty acids increase markedly at the expense of the omega 6 fatty acids.
There may even be other benefits to fish products. Certain mice that die at an early age of autoimmune disease have been given prostaglandin E.sub.1 (PGE.sub.1) or menhaden oil diets and exhibited markedly longer lifespans and a virtual disappearance of immune mediated glomerulonephritis. (Kelley, V. E., A. Winkelstein, S. Isui, and F. J. Dixon. Prostaglandin E.sub.1 Inhibits T-Cell Proliferation and Renal Disease in MRL/1 Mice. Clin Immunology & Immunopathology 21: 190-203, 1981; Prickett, J. D., D. R. Robinson, and A. D. Steinberg. Dietary Enrichment with the Polyunsaturated Fatty Acid Eicosapentaenoic Acid Prevents Proteinuria and Prolongs Survival in NZB X NZW F.sub.1 Mice. J Clin Invest 68: 556-559, 1981) Fish oil was also found to be beneficial in a marine model of anyloidosis. (Hayes, K. D., E. Cathcart, C. A. Leslie, and S. N. Meydani. Dietary Fish Oil Alters Prostaglandin Metabolism to Decrease Platelet Aggregation in Monkeys and Anyloidosis in Mice. Proc of Conf on Omega-3 Fatty Acids. Reading, England: Reading University, 131-132, Jul 16-18, 1984).
The beneficial effects of fish oils in inflammatory disorders stem, at least in part, from the interaction of EPA and arachidonic acid with the enzyme lipoxygenase in inflammatory cells (neutrophils and monocytes). In the presence of EPA these cells produce less Leukotriene B.sub.4 (a major component of inflammatory response) and small amounts of Leukotriene B.sub.5. (Lee, T. H., R. L. Hoover, J. D. Williams, et al. Effect of Dietary Enrichment with Eicosapentaenoic and Docosahexaenoic Acids on in vitro Neutrophil and Monocyte Leukotriene Generation and Neutrophil Function. N Engl J. Med 312(19): 1217-1224, 1985) LTB.sub.5 is at least 30 times less potent than LTB.sub.4 in causing aggregation, chemokinesis and degranulation of human neutrophils in vitro. The potency of LTB.sub.5 in potentiating bradykinin-induced plasma exudation, which is probably attributable to its leukotactic activity, is as least 10 times lower than that of LTB.sub.4. (Terano, T., J. A. Salmon, and S. Moncada. Biosynthesis and Biological Activity of Leukotriene B.sub.5. Prostaglandins 27(2): 217-232, 1984)
U.K. patent application GB No. 2 139 889A discloses an emulsion for intravenous use which contains a fatty acid containing 20-22 carbon atoms or an ester of the fatty acid, a vegetable oil, an emulsifier and water.
It is an object of this invention to provide a lipid emulsion for intravenous therapy and treatment of thrombotic disease. It is a further object of this invention to provide an emulsion which inhibits formation of certain prostaglandins. It is a further object of this invention to provide such an emulsion wherein the concentrations of free fatty acids are below toxic levels.
Other objects appear hereinafter.